RX 330 Tire Pressure Sensors work as advertised
03-28-05, 01:57 PM
#1
Out of Warranty
Thread Starter
RX 330 tire pressure sensors work - as advertised
Saturday night on the way home, my low tire pressure warning light came on. I exited the freeway and pulled into a gas station to take a look. No visible problem, and my cheap tire gauge showed none either. My wife’s car has the good gauge, naturally. 
When I turned off the ignition, the warning reset, and there was no further problem in the next 20 miles home.
Sunday, out on the freeway, the warning light came on again. Still no obvious problem, so I continued on. About 5 miles later, the light went out. After being parked at our destination for about 4 hours, finally the right rear tire looked a little low. I limped to a nearby gas station and checked – it was about 10 lbs low! I aired the tire up to 35 lbs and drove home. No more problems.
Tire still OK this morning, still no recurrence of the warning light. I drove to the Lexus dealership to get it checked, not trusting the local flat-busters. They found a small nail had produced a very slow leak.
Lessons learned:
When I turned off the ignition, the warning reset, and there was no further problem in the next 20 miles home. Sunday, out on the freeway, the warning light came on again. Still no obvious problem, so I continued on. About 5 miles later, the light went out. After being parked at our destination for about 4 hours, finally the right rear tire looked a little low. I limped to a nearby gas station and checked – it was about 10 lbs low! I aired the tire up to 35 lbs and drove home. No more problems.
Tire still OK this morning, still no recurrence of the warning light. I drove to the Lexus dealership to get it checked, not trusting the local flat-busters. They found a small nail had produced a very slow leak.
Lessons learned:
- Tire pressure monitor compares revolutions of wheels and is able to detect very small discrepancies in tire pressure.
- It won’t tell you which tire is low, and this can be frustrating, unless you take time to check them all with an accurate gauge.
- In the case of a very slow leak, the warning light may go out as flexing sidewall warms air and restores pressure and diameter.
- Service writer says his wife has experienced the same thing, but with a faster leak, it may require as much as a mile for the sensor to decide there is a problem – at which point the tire is well and truly flat.
- When the light comes on, pull over, it’s not lying.
03-28-05, 05:20 PM
#2
Originally Posted by Lil4X
Saturday night on the way home, my low tire pressure warning light came on. I exited the freeway and pulled into a gas station to take a look. No visible problem, and my cheap tire gauge showed none either. My wife’s car has the good gauge, naturally. When I turned off the ignition, the warning reset, and there was no further problem in the next 20 miles home.
Sunday, out on the freeway, the warning light came on again. Still no obvious problem, so I continued on. About 5 miles later, the light went out. After being parked at our destination for about 4 hours, finally the right rear tire looked a little low. I limped to a nearby gas station and checked – it was about 10 lbs low! I aired the tire up to 35 lbs and drove home. No more problems.
Tire still OK this morning, still no recurrence of the warning light. I drove to the Lexus dealership to get it checked, not trusting the local flat-busters. They found a small nail had produced a very slow leak.
Lessons learned:
When I turned off the ignition, the warning reset, and there was no further problem in the next 20 miles home. Sunday, out on the freeway, the warning light came on again. Still no obvious problem, so I continued on. About 5 miles later, the light went out. After being parked at our destination for about 4 hours, finally the right rear tire looked a little low. I limped to a nearby gas station and checked – it was about 10 lbs low! I aired the tire up to 35 lbs and drove home. No more problems.
Tire still OK this morning, still no recurrence of the warning light. I drove to the Lexus dealership to get it checked, not trusting the local flat-busters. They found a small nail had produced a very slow leak.
Lessons learned:
- Tire pressure monitor compares revolutions of wheels and is able to detect very small discrepancies in tire pressure.
- It won’t tell you which tire is low, and this can be frustrating, unless you take time to check them all with an accurate gauge.
- In the case of a very slow leak, the warning light may go out as flexing sidewall warms air and restores pressure and diameter.
- Service writer says his wife has experienced the same thing, but with a faster leak, it may require as much as a mile for the sensor to decide there is a problem – at which point the tire is well and truly flat.
- When the light comes on, pull over, it’s not lying.
Is the tire pressure sensor set for a specified psi? 29psi??
I know that 30psi is the recommended pressure. Anyone knows?
03-28-05, 05:40 PM
#3
The Owner's Manual tells you how to calibrate the system.
The best thing to do is set the tires to the pressure you want, and then calibrate it. (That's part of the pre-delivery checklist when the car is new.)
Also bear in mind that this system is a differential design - it's not based on absolute pressure. It's based on detection of the fact that one wheel is different from the others. If all 4 went flat at the same time, you wouldn't get a warning.
The people that lobbied the U.S. goverment to make a tire pressure warning system mandatory on new cars consider this system a cop-out. They wanted to mandate something that tells you the actual pressure in all 4 wheels and displays it. Some cars offer that, but the differential system meets U.S. standards.
I believe tire pressure warning systems are required on all new cars in the U.S. starting in 2006, thanks to the Ford Explorer / Firestone tire fiasco.
The best thing to do is set the tires to the pressure you want, and then calibrate it. (That's part of the pre-delivery checklist when the car is new.)
Also bear in mind that this system is a differential design - it's not based on absolute pressure. It's based on detection of the fact that one wheel is different from the others. If all 4 went flat at the same time, you wouldn't get a warning.
The people that lobbied the U.S. goverment to make a tire pressure warning system mandatory on new cars consider this system a cop-out. They wanted to mandate something that tells you the actual pressure in all 4 wheels and displays it. Some cars offer that, but the differential system meets U.S. standards.
I believe tire pressure warning systems are required on all new cars in the U.S. starting in 2006, thanks to the Ford Explorer / Firestone tire fiasco.
03-28-05, 06:08 PM
#4
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Glad to hear it works. Since our new home (and subdivision) is being built, I'm a little worried about nails around the neighborhood when I go to check on the house.
03-28-05, 09:56 PM
#5
Originally Posted by rxdriver
The Owner's Manual tells you how to calibrate the system.
The best thing to do is set the tires to the pressure you want, and then calibrate it. (That's part of the pre-delivery checklist when the car is new.)
Also bear in mind that this system is a differential design - it's not based on absolute pressure. It's based on detection of the fact that one wheel is different from the others. If all 4 went flat at the same time, you wouldn't get a warning.
The people that lobbied the U.S. goverment to make a tire pressure warning system mandatory on new cars consider this system a cop-out. They wanted to mandate something that tells you the actual pressure in all 4 wheels and displays it. Some cars offer that, but the differential system meets U.S. standards.
I believe tire pressure warning systems are required on all new cars in the U.S. starting in 2006, thanks to the Ford Explorer / Firestone tire fiasco.
The best thing to do is set the tires to the pressure you want, and then calibrate it. (That's part of the pre-delivery checklist when the car is new.)
Also bear in mind that this system is a differential design - it's not based on absolute pressure. It's based on detection of the fact that one wheel is different from the others. If all 4 went flat at the same time, you wouldn't get a warning.
The people that lobbied the U.S. goverment to make a tire pressure warning system mandatory on new cars consider this system a cop-out. They wanted to mandate something that tells you the actual pressure in all 4 wheels and displays it. Some cars offer that, but the differential system meets U.S. standards.
I believe tire pressure warning systems are required on all new cars in the U.S. starting in 2006, thanks to the Ford Explorer / Firestone tire fiasco.
I meant to say when it came out from the dealer (pre-delivery checklist). What do they set the tire pressure psi warning at?? I read the part on calibrating on the manual...........just wondering what the dealer set it to?
03-28-05, 10:01 PM
#6
Lexus Test Driver
Well never know what the dealer set it at! Probably best thing to do is do it yourself, so you know what the pressure is.
Im going to have to do that to mine-----come to think of it
Im going to have to do that to mine-----come to think of it
03-28-05, 10:32 PM
#7
Out of Warranty
Thread Starter
Originally Posted by Lextranny
What do they set the tire pressure psi warning at?? I read the part on calibrating on the manual...........just wondering what the dealer set it to?
If you set your tires to whatever pressure you desire, then calibrate the system, you will get a warning light if relative wheel speed exceeds some small value (I believe corresponding to a pressure as little as 3-4 psi), you will get a low tire warning.
Last edited by Lil4X; 03-28-05 at 10:37 PM.
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03-29-05, 03:15 AM
#8
Originally Posted by Lextranny
Is the tire pressure sensor set for a specified psi? 29psi??
I know that 30psi is the recommended pressure. Anyone knows?
I know that 30psi is the recommended pressure. Anyone knows?
03-29-05, 05:49 AM
#9
Lexus Test Driver
Originally Posted by Lil4X
The sensors do not directly measure pressure, thus are not "set" for a pressure. This system uses the ABS sensors that read wheel speed to interpret a wheel turning faster than the others (due to reduced diameter) as being lower in pressure than the others. If you have all four wheels turning at the same speed, they can be assumed to be at the same pressure. It doesn't matter if that pressure is 40 psi or 20 psi - so long as they are all turning at the same speed, no warning is given.
If you set your tires to whatever pressure you desire, then calibrate the system, you will get a warning light if relative wheel speed exceeds some small value (I believe corresponding to a pressure as little as 3-4 psi), you will get a low tire warning.
If you set your tires to whatever pressure you desire, then calibrate the system, you will get a warning light if relative wheel speed exceeds some small value (I believe corresponding to a pressure as little as 3-4 psi), you will get a low tire warning.
I had a low pressure light come and it went off after I raised the air pressure (left the engine running). The process I used is covered here, https://www.clublexus.com/forums/sho...d.php?t=155433 so its no fluke. The pressure had to exceed a certain threshold to turn the lamp off.
I also have a GX470 and believe it operates the same way. If I'm right and the RX shares the same system as the GS, then the speed sensor is the sole sensor concept has to be wrong.
03-29-05, 03:46 PM
#13
LexT, now that's just not right! 
Just got this baby a couple years ago and at 23k she's not even broken in. But i'm sort of thinkin the same thing! Gotta get permission to upgrade though . . . ....
Wife might want something first!
Just got this baby a couple years ago and at 23k she's not even broken in. But i'm sort of thinkin the same thing! Gotta get permission to upgrade though . . . ....
Wife might want something first!
03-30-05, 04:32 AM
#14
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Crap my $29,000 350z has the tire pressure monitor with individual psi reading for each tire, however our $42,000 RX330 only beeps and flashes a light. WTF? Of course there are a bunch of stuff missing on the Nissan that the RX does have, hence, why I purchased it. 
